JP2013099708A - Method and device for roll-coating to ribbon-like substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for roll-coating which can efficiently perform stable thin film coating at high speed, when coating multiple layers on a ribbon-like substrate traveling continuously.SOLUTION: In the method for roll-coating, an applicator roll 5 is made contact with a substrate 1, which is traveling continuously, to coat a coating liquid on the substrate 1. multilayer coating including at least two layers is applied to the applicator roll 5 with a slit die 7. In this state, when the thickness of the coating liquid on the applicator roll 5 is defined to be t(μm), the roll diameter D(mm) of the applicator roll 5 is defined as D≤3.3t+133.3, and the adjustment is performed to set the rotation speed Vof the applicator roll 5 and the speed Vof the substrate 1 to satisfy 0.9≤V/V≤1.2. The coating liquid which has not been transcribed from the applicator 5 to the substrate 1 and remained is removed by a scraper 6.

Description

  The present invention relates to a roll coating method and a coating apparatus for coating a coating liquid continuously on a strip-shaped substrate.

  Conventionally, in order to impart performance such as corrosion resistance, workability, aesthetics, insulation, etc. to a continuous belt-like substrate (for example, steel strip), various coating films are formed on the metal surface. Yes. As this processing method, a roll coater (roll coating device) is generally used, and this roll coater method makes an applicator roll contact a substrate with respect to a continuously running substrate, and at a contact portion. The coating liquid is applied by rotating in the direction opposite to the base material traveling direction.

  In recent years, multi-layer coatings may be required in coating design due to increasing needs for high added value such as high corrosion resistance and high insulation.

  As a multilayer coating method, as shown in FIG. 4, a slit die coater type coating device 31 (for example, a patent) that applies a multilayer coating by bringing a slit die (slit die coater) 7 having a plurality of slits into contact with the substrate 1. As shown in FIG. 5, and as shown in FIG. 5, a curtain coater type coating device 32 (multiple coating is applied to the base material 1 by a curtain coater 9 that supplies the coating liquid from a plurality of slits and hangs on the base material 1 in a curtain shape For example, see Patent Document 2). 4 and 5, reference numeral 8 denotes a backup roll, and reference numeral 10 denotes a suction device (suction device).

JP 2004-160274 A JP 2006-150184 A

  However, when the slit die method shown in FIG. 4 is used, in order to reduce the film thickness, the gap between the substrate 1 and the die (slit die) 7 for supplying the coating liquid is brought close to the desired film thickness. Necessary, if it is a smooth base material such as a glass substrate, proximity can be made, but in the case of a steel strip that runs continuously, shape variation occurs in both the width direction and the longitudinal direction, so the proximity of the die is Have difficulty. Further, in the case of the curtain coater method shown in FIG. 5, since the minimum liquid flow rate at which the curtain can be formed is determined by the coating liquid, the film becomes thick unless the line speed is increased to some extent. However, when the line speed is increased, coating unevenness such as air entrainment is caused, so that thin film coating is difficult.

  On the other hand, when performing multilayer coating by the roll coater method, generally, the multilayer coating is performed in such a manner that the first layer is coated and then the second layer is coated. If the second layer is applied while the eyes are liquid layers, the first layer is scraped off, and a laminated film cannot be constructed. Therefore, it is necessary to apply the second layer through a drying process after application. However, in that case, the coating process and the drying process are required twice, and the running cost increases.

  The present invention has been made in view of the above circumstances, and a roll capable of efficiently performing high-speed and stable thin film coating when performing multilayer coating on a continuously running belt-like substrate. The object is to provide a coating method and apparatus.

  In order to solve the above problems, the present invention has the following features.

[1] In a roll coating method in which an applicator roll is brought into contact with the base material on a belt-like base material that runs continuously, and a coating liquid is applied by rotating the applicator roll in a direction opposite to the base material traveling direction at the contact portion. , two or more layers of the multilayer coating by a slit die with respect to the applicator roll, if the coating liquid film thickness on the applicator roll at that time was t _{a (μm),} the roll diameter D _a of the applicator roll (Mm) is set to D _a ≦ 3.3 t _a +133.3 so that the rotation speed V _{a of the} applicator roll and the speed V _{L of the} base material are 0.9 ≦ V _a / V _L ≦ 1.2. A roll coating method on a strip-shaped substrate, wherein the coating liquid remaining after being adjusted and not transferred from the applicator roll to the substrate is removed by a scraping device.

[2] In a roll coating method in which an applicator roll is brought into contact with the base material on a continuously running belt-like base material, and the coating liquid is applied by rotating the contact portion in a direction opposite to the base material traveling direction. When the applicator roll is coated with two or more layers by a slit die through an intermediate roll, and the coating film thickness on the intermediate roll is t _c (μm), the intermediate roll Roll diameter D _c (mm) of D _c ≦ 3.3t _c +133.3, and roll diameter D _a (mm) of the applicator roll is set to D _a ≦ 3.3t _c +133.3, and the intermediate roll supplying the coating liquid to the applicator roll by rotating in the opposite direction to the contact portion between the applicator roll, the rotational speed V of the intermediate rolls And the rotational velocity _{V a} of the applicator roll _{0.9 ≦ V c / V a ≦} 1.2 , and the rotational speed _{V a} and the speed _{V L} is 0.9 ≦ _V a / V of the substrate of the applicator roll A roll coating method on a belt-shaped substrate, wherein the coating liquid is adjusted so that _L ≦ 1.2, and the coating liquid remaining without being transferred from the intermediate roll to the applicator roll is removed by a scraping device.

  [3] The roll application method to the belt-like substrate according to [1] or [2], wherein the applicator roll is a rubber-coated roll obtained by lining a metal roll with rubber.

  [4] The roll coating method for a strip-shaped substrate according to any one of [1] to [3], wherein a suction mechanism for generating a negative pressure is disposed on the slit die on the upstream side of the coating part. .

[5] In a roll coating apparatus that applies a coating liquid by contacting an applicator roll with a belt-like base material that runs continuously and rotating in a direction opposite to the base material traveling direction at the contact portion. , two or more layers of the multilayer coating by a slit die with respect to the applicator roll, if the coating liquid film thickness on the applicator roll at that time was t _{a (μm),} the roll diameter D _a of the applicator roll (Mm) is D _a ≦ 3.3 t _a +133.3, and the rotation speed V _{a of the} applicator roll and the speed V _{L of the} base material are 0.9 ≦ V _a / V _L ≦ 1.2. The applicator roll is provided with a scraping device that removes the coating liquid remaining without being transferred from the applicator roll to the substrate. Roll applicator for belt-like substrate.

[6] A roll coating apparatus that applies a coating liquid by contacting an applicator roll with the substrate on a continuously running belt-like substrate and rotating the contact portion in a direction opposite to the substrate traveling direction. When the coating film thickness on the intermediate roll at that time is t _c (μm), the intermediate layer is applied to the applicator roll. The roll diameter D _c (mm) of the roll is D _c ≦ 3.3t _c +133.3, and the roll diameter D _a (mm) of the applicator roll is D _a ≦ 3.3t _c +133.3, supplying the coating liquid to the applicator roll by the intermediate rolls are rotated in opposite directions at the contact portion between the applicator roll, the rotational speed V _c of the intermediate rolls The rotational speed _{V a} of the applicator roll _{0.9 ≦ V c / V a ≦} 1.2 , and the speed _{V L} of the base material and the rotational speed _{V a} of the applicator roll 0.9 ≦ _V a / _{V L} A strip-shaped base, characterized in that a scraping device that is adjusted so as to satisfy ≦ 1.2 and removes a coating solution remaining without being transferred from the intermediate roll to the applicator roll is disposed in the intermediate roll. Roll applicator for materials.

  [7] The roll applicator for a band-shaped substrate according to [5] or [6], wherein the applicator roll is a rubber-coated roll obtained by lining a metal roll with rubber.

  [8] The roll die coating device for the strip-shaped substrate according to any one of [5] to [7], wherein the slit die includes a suction mechanism that generates a negative pressure upstream of the coating unit. .

  In the present invention, when performing multilayer coating on a continuously running belt-like substrate, it is possible to efficiently perform high-speed and stable thin film coating.

It is a side view which shows Embodiment 1 of this invention. It is a side view which shows Embodiment 2 of this invention. It is a side view which shows the slit die | dye used in embodiment of this invention. It is a side view which shows a prior art (slit-die system). It is a side view which shows a prior art (curtain coater system).

  Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 1 is a side view showing a roll coating apparatus 21 according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the roll coating apparatus 21 according to the first embodiment makes an applicator roll 5 come into contact with the base material 1 and makes contact with the belt-like base material (for example, steel strip) 1 that runs continuously. It is a roll coating device that transfers and coats the coating liquid onto the base material 1 by rotating it in the direction opposite to the direction of travel of the base material 1. The multi-layer coated applicator roll 6 is brought into contact with the substrate 1 to transfer and apply the multilayer coating solution to the substrate 1 (multi-layer coating). In FIG. 1, 2 is a coating liquid recovery container, 3 is a coating liquid, 6 is a scraping device, and 8 is a backup roll.

  As the slit die 7 used here, for example, in the case of two-layer coating, as shown in FIG. 3, it is provided with two coating liquid supply portions 7a and 7b for supplying different coating liquids, A coating liquid supply unit 7a, 7b provided with a suction unit (suction unit) 7c that generates a negative pressure upstream of the applicator roll 5 in the rotation direction is used. By generating negative pressure upstream of the applicator roll 5 in the rotation direction of the applicator roll 5 of the coating liquid supply unit 7a, 7b, the shape of the meniscus supplied with the coating liquid from the coating liquid supply unit 7a, 7b is stably maintained, and the film thickness On the other hand, it is possible to secure a gap several times as large. The supply of the coating liquid to the slit die 7 is performed by a pump (not shown) that can stably discharge a constant flow rate. Then, a stable multilayer liquid film application is performed on the applicator roll 5 by adjusting the negative pressure of the suction portion 7c, the gap between the applicator roll 5 and the slit die 7, and the like.

Next, after applying the multilayer liquid film from the slit die 7 to the applicator roll 5, the multilayer coating liquid on the applicator roll 5 rotating in the reverse direction is applied to the substrate 1 at the contact portion between the applicator roll 5 and the substrate 1. When transferring, the shape of the liquid meniscus greatly affects the multilayer state. As a result of the experiment, when the coating liquid film thickness on the applicator roll 5 is t _a (μm), the liquid meniscus shape is obtained by making the roll diameter D _a (mm) of the applicator roll satisfy the following expression (1). Has been found to provide a stable multilayer film.

D _a ≦ 3.3 t _a +133.3 (1)

  This is considered to be because the contact portion between the applicator roll 5 and the meniscus is reduced, the area where the meniscus is affected by the disturbance is reduced, and the effect of stabilizing the meniscus is improved.

Further, the speed ratio V _a / V _L between the rotation speed (peripheral speed) V _{a of} the applicator roll 5 and the running speed (line speed) V _L of the substrate 1 is adjusted so as to satisfy the following expression (2). There is a need to.

0.9 ≦ V _a / V _L ≦ 1.2 (2)

This is because when the speed ratio V _a / V _L is smaller than 0.9 or larger than 1.2, the meniscus between the applicator roll 5 and the substrate 1 is disturbed, and the multi-layer state is not maintained and stirring is performed. Because it will end up.

In order to maintain a more beautiful layered structure, the speed ratio V _a / V _L is preferably 0.95 or more and 1.1 or less.

  And it is necessary to attach to the applicator roll 5 a scraping device 6 for removing the coating liquid remaining without being transferred from the applicator roll 5 to the substrate 1. This is because if the coating liquid remaining without being transferred to the substrate 1 is supplied as it is to the coating portion of the slit die 7 (tip portions of the coating liquid supply portions 7a and 7b), stable coating is hindered. . The scraping device 6 may be any device as long as it can scrape off the coating solution. For example, it is easy to install a blade. The material of the blade may be metal or rubber as long as uniform scraping is obtained.

  In addition, when the base material 1 is a metal band such as a steel band, the applicator roll 5 is a rubber-coated roll in which rubber is lined on the surface of the metal roll. By using a rubber-coated roll, the influence of eccentricity can be absorbed by elastic deformation, and unevenness in appearance and change in the amount of adhesion can be reduced. The rubber lining thickness is preferably about 5 to 40 mm. The rubber hardness is preferably about 40Hs to 80Hs.

  Thus, in Embodiment 1 of the present invention, by providing the above-described configuration, when performing multi-layer coating on a continuously running substrate, high-speed and stable thin-film coating is efficiently performed. It can be carried out.

[Embodiment 2]
FIG. 2 is a side view showing a roll coating apparatus 22 according to Embodiment 2 of the present invention.

  The roll coating apparatus 21 according to Embodiment 1 of the present invention described above can perform stable coating when the amount of the substrate 1 to be coated is small, but requires a large amount of substrate and continuous coating for a long time. In such a case, there is a concern that the applicator roll 5 may be worn and become a non-uniform shape, resulting in a coating defect.

  Therefore, in order to cope with mass production by continuous operation, in the roll coating apparatus 22 in the second embodiment, as shown in FIG. 2, the basic configuration is the same as the roll coating apparatus 21 in the first embodiment shown in FIG. In the same manner, an intermediate roll 4 for transferring the coating liquid supplied from the slit die 7 to the applicator roll 5 is provided between the slit die 7 and the applicator roll 5. As a result, two or more layers (multilayer coating) are applied from the slit die 7 to the applicator roll 5 via the intermediate roll 4, and the multilayer-coated applicator roll 6 is brought into contact with the substrate 1. Multilayer coating solution is transferred and applied (multilayer coating).

  Here, the intermediate roll 4 is a flat roll having a mirror-finished surface. Further, the rotation directions of the intermediate roll 4 and the applicator roll 5 are opposite to each other between the intermediate roll 4 and the applicator roll 5 and between the applicator roll 5 and the substrate 1.

At that time, in the same manner as described in the first embodiment, when the coating liquid film thickness on the intermediate roll 4 is t _c (μm), the roll diameter D _c (mm) of the intermediate roll 4 and the applicator roll The roll diameter D _a (mm) satisfies the following expressions (3) and (4), respectively.

D _c ≦ 3.3 t _c +133.3 (3)
D _a ≦ 3.3 t _c +133.3 (4)

  As a result, the liquid meniscus shape is stabilized and a beautiful multilayer film is obtained.

Further, by the same method as described in embodiment 1, the speed ratio V _{c /} V _a between the rotational speed (outer circumferential speed) V _a rotational speed (outer circumferential speed) V _c and applicator roll 5 of the intermediate rolls 4, The speed ratio V _a / V _L between the rotational speed (peripheral speed) V _{a of the} applicator roll 5 and the travel speed (line speed) V _L of the substrate 1 satisfies the following formulas (5) and (6), respectively. Need to be adjusted.

0.9 ≦ V _c / V _a ≦ 1.2 (5)
0.9 ≦ V _a / V _L ≦ 1.2 (6)

In order to maintain a more beautiful layered structure, it is preferable that the speed ratios V _c / V _a and V _a / V _L are 0.95 or more and 1.1 or less, respectively.

  Similarly to the method described in the first embodiment, the intermediate roll 4 has a scraping device (for example, a blade) 6 for removing the coating liquid remaining without being transferred from the intermediate roll 4 to the applicator roll 5. It is necessary to install. The scraping device 6 may be attached to the applicator roll 5.

  Thus, in Embodiment 2 of the present invention, by providing the above-described configuration, when performing multi-layer coating on a continuously running substrate, a thin film coating that is stable at high speed over a long period of time. Can be performed efficiently.

  In the first and second embodiments, the base material 1 is applied to one side of the base material 1 while being wound around the backup roll 8. However, in the present invention, a roll coating device is provided on both sides of the base material. It can also be applied to the case where both are applied simultaneously.

  Further, the base material is not limited to a steel strip, and other metal strips such as aluminum, paper, films, and the like can also be targeted.

  The present invention will be described in detail with reference to the following examples of the present invention, comparative examples, and conventional examples.

  As Examples 1-3 of the present invention, based on Embodiment 1 of the present invention described above, using the roll coating apparatus 21 shown in FIG. 1, a coil of a galvanized steel sheet having a plate thickness of 0.8 mm and a plate width of 300 mm is used. Then, two-layer coating was performed under the coating conditions shown in Table 1.

At that time, the applicator roll 5 was a rubber-coated roll lined with urethane rubber. The rubber lining thickness is 20 mm, and the hardness of the urethane rubber is Hs55 °. Roll diameter _{D a} of the applicator roll 5 was set to 150 mm. For the coating solution, the lower layer has a viscosity coefficient of 2.0 mPa · s (at a liquid temperature of 20 ° C.) and a solid content concentration of 6 wt%, and the upper layer has a viscosity coefficient of 4.0 mPa · s (at a liquid temperature of 20 ° C.). The 8 wt% material was used. The coating liquid film thickness, the upper layer, the liquid film on the applicator roll 5 to the lower both thickness 5 [mu] m, the liquid film thickness t _a of the second layer total was adjusted to 10 [mu] m. Thereby, the above-described formula (1) (D _a ≦ 3.3 t _a +133.3) was satisfied. Further, the speed ratio V _a / V _L between the rotation speed (peripheral speed) V _{a of} the applicator roll 5 and the travel speed (line speed) V _L of the substrate 1 is the above-described formula (2) (0.9 ≦ V _a / V _L ≦ 1.2) was adjusted.

On the other hand, as Comparative Examples 1 and 2, the other conditions are the same as those of Examples 1 to 3 of the present invention, and as shown in Table 1, the speed ratio V _a / V _L is expressed by the formula (2) ( Two layers were applied under conditions that did not satisfy 0.9 ≦ V _a / V _L ≦ 1.2).

  Further, as Examples 4 to 6 of the present invention, a coil of a galvanized steel sheet having a plate thickness of 0.8 mm and a plate width of 300 mm using the roll coating apparatus 22 shown in FIG. 2 based on the second embodiment of the present invention. On the other hand, two-layer coating was performed under the coating conditions shown in Table 1.

At that time, a metal roll having a flat surface subjected to hard chrome plating was used as the intermediate roll 4, and a rubber-coated roll lined with urethane rubber was used as the applicator roll 5. The rubber lining thickness is 20 mm, and the hardness of the urethane rubber is Hs55 °. Roll diameter _{D a} of the roll diameter _{D c} and applicator roll 5 of the intermediate rolls 4 were both set to 150 mm. For the coating solution, the lower layer has a viscosity coefficient of 2.0 mPa · s (at a liquid temperature of 20 ° C.) and a solid content concentration of 6 wt%, and the upper layer has a viscosity coefficient of 4.0 mPa · s (at a liquid temperature of 20 ° C.). The 8 wt% material was used. The coating film thickness was adjusted so that the liquid film thickness on the intermediate roll 4 was 5 μm for both the upper layer and the lower layer, and the total liquid film thickness t _c of the two layers was 10 μm. As a result, the above-described expression (3) (D _c ≦ 3.3 t _c +133.3) and expression (4) (D _a ≦ 3.3 t _a +133.3) were satisfied. The rotational speed (outer circumferential speed) _{V c} and the rotational speed (outer circumferential speed) of the speed ratio _V c / _{V a} and applicator roll 5 between the rotational speed (outer circumferential speed) _{V a} of the applicator roll 5 of the intermediate rolls 4 and _{V a} Regarding the speed ratio V _a / V _{L to} the running speed (line speed) V _L of the base material 1, the above-described equations (5) (0.9 ≦ V _c / V _a ≦ 1.2) and (6), respectively. Adjustment was made so as to satisfy the formula (0.9 ≦ V _a / V _L ≦ 1.2).

On the other hand, as Comparative Examples 3 and 4, the other conditions were the same as those of Invention Examples 4 to 5, and as shown in Table 1, the speed ratio V _c / V _a and the speed ratio V _a / V _L were The two-layer coating is performed under the condition that does not satisfy the above-mentioned formula (5) (0.9 ≦ V _c / V _a ≦ 1.2) and (6) formula (0.9 ≦ V _a / V _L ≦ 1.2). Went.

  Further, as the conventional examples 1 and 2, using a slit die coater type coating device 31 shown in FIG. 4 and a curtain coater type coating device 32 shown in FIG. Two-layer coating was performed on the coil of a 300 mm galvanized steel sheet under the coating conditions shown in Table 1.

  And about these invention examples 1-6, comparative examples 1-4, and the prior art examples 1 and 2, evaluation of the application | coating external appearance after drying and confirmation of the lamination | stacking state of the coating-film cross section were performed. Specifically, the sample was cut out after baking and drying, and the cross section was observed visually and by SEM. The results are shown in Table 1.

Next, in order to verify the relationship of the above equation (1) (D _a ≦ 3.3 t _a +133.3) regarding the roll diameter D _a of the applicator roll 5 and the liquid film thickness t _a on the applicator roll 5, as invention examples 11 to 13, other conditions are the same as Working example 1-3, as shown in Table 2, by changing the liquid film thickness t _a and the roll diameter D _a was 2-layer coating .

On the other hand, as Comparative Examples 11 to 13, the other conditions were the same as those of Invention Examples 11 to 13, and as shown in Table 2, the above-described formula (1) (D _a ≦ 3.3 t _a +133. Two-layer coating was performed under conditions that did not satisfy the relationship of 3).

  And about these invention examples 11-13 and comparative examples 11-13, evaluation of the application | coating external appearance after drying and confirmation of the lamination | stacking state of a coating-film cross section were performed. Specifically, the sample was cut out after baking and drying, and the cross section was observed visually and by SEM. The results are shown in Table 2.

  As shown in Tables 1 and 2, in Inventive Examples 1-6, 11-13, a two-layer film having a coating film thickness of about 5.0 μm can be uniformly applied to the upper and lower layers. . On the other hand, in Comparative Examples 1-4, 11-13, the upper layer and the lower layer were mixed and a laminated film could not be obtained. Further, in Conventional Examples 1 and 2, it was impossible to form a dull or curtain liquid film, and stable coating could not be performed.

1 Base material (band-shaped base material)
2 Coating liquid collection container 3 Coating liquid 4 Intermediate roll 5 Applicator roll 6 Scraping device (blade)
7 Slit Die (Slit Die Coater)
7a Coating liquid supply part 7b Coating liquid supply part 7c Suction part (suction part)
8 Backup roll 9 Curtain coater 10 Suction device (suction device)
21 Roll coating device 22 Roll coating device 31 Slit die coater type coating device 32 Curtain coater type coating device

Claims (8)

In the roll coating method in which the applicator roll is brought into contact with the base material on the belt-like base material that runs continuously and the coating liquid is applied by rotating the applicator roll in the direction opposite to the base material traveling direction at the contact portion. two or more layers of the multilayer coating by slit die for a role, if the coating liquid film thickness on the applicator roll at that time was t _{a (μm),} the roll diameter of the applicator roll D _{a (mm)} And D _a ≦ 3.3 t _a +133.3, and adjustment is performed so that the rotation speed V _{a of the} applicator roll and the speed V _{L of the} base material are 0.9 ≦ V _a / V _L ≦ 1.2. A method of applying a roll to a belt-shaped substrate, wherein the coating liquid remaining without being transferred from the applicator roll to the substrate is removed by a scraping device. In the roll coating method in which the applicator roll is brought into contact with the base material on the belt-like base material that runs continuously and the coating liquid is applied by rotating the applicator roll in the direction opposite to the base material traveling direction at the contact portion. When a multi-layer coating of two or more layers is applied to the roll with a slit die through an intermediate roll, and the coating liquid film thickness on the intermediate roll at that time is t _c (μm), the roll diameter of the intermediate roll D _c (mm) is set to D _c ≦ 3.3t _c +133.3, the roll diameter D _a (mm) of the applicator roll is set to D _a ≦ 3.3t _c +133.3, and the intermediate roll is set to the applicator. supplying the coating liquid to the applicator roll by rotating in opposite directions at the contact portion with the roll, said intermediate roll rotation speed V _c and the front Rotational speed _{V a} of the applicator roll _{0.9 ≦ V c / V a ≦} 1.2 , and the speed _{V L} of the base material and the rotational speed _{V a} of the applicator roll 0.9 ≦ _V a / _{V L} ≦ A roll coating method on a strip-shaped substrate, wherein the coating liquid is adjusted to 1.2 and the coating liquid remaining without being transferred from the intermediate roll to the applicator roll is removed by a scraping device.   The roll applicator method according to claim 1 or 2, wherein the applicator roll is a rubber-coated roll obtained by lining a metal roll with rubber.   The roll coating method for a strip-shaped substrate according to any one of claims 1 to 3, wherein a suction mechanism for generating a negative pressure on the upstream side of the coating part is disposed on the slit die. The applicator roll is a roll coating apparatus that applies a coating liquid by contacting an applicator roll with the base material continuously running and rotating in the contact portion in a direction opposite to the base material traveling direction. two or more layers of the multilayer coating by slit die for a role, if the coating liquid film thickness on the applicator roll at that time was t _{a (μm),} the roll diameter of the applicator roll D _{a (mm)} D _a ≦ 3.3 t _a +133.3, and the rotation speed V _{a of the} applicator roll and the speed V _{L of the} base material are adjusted so that 0.9 ≦ V _a / V _L ≦ 1.2. A strip-like device is provided on the applicator roll, wherein a scraping device for removing the coating liquid remaining without being transferred from the applicator roll to the base material is disposed. Roll coating device for substrates. In the roll coating apparatus for applying the coating liquid by continuously rotating the applicator roll in contact with the base material and rotating in the contact portion in the direction opposite to the base material traveling direction with respect to the belt-like base material that runs continuously, When an applicator roll is coated with two or more layers by a slit die through an intermediate roll, and the coating film thickness on the intermediate roll is t _c (μm), the roll of the intermediate roll The diameter D _c (mm) is D _c ≦ 3.3t _c +133.3, the roll diameter D _a (mm) of the applicator roll is D _a ≦ 3.3t _c +133.3, and the intermediate roll is supplying the coating liquid to the applicator roll by rotating in the opposite direction at the contact portion between the applicator rolls, wherein the rotational speed V _c of the intermediate rolls Rotational speed _{V a} is _{0.9 ≦ V c / V a ≦} 1.2 next to applicator roll, the speed _{V L} of the base material and the rotational speed _{V a} of the applicator roll 0.9 ≦ _V a / _{V L} A strip-shaped base, characterized in that a scraping device that is adjusted so as to satisfy ≦ 1.2 and removes a coating solution remaining without being transferred from the intermediate roll to the applicator roll is disposed in the intermediate roll. Roll applicator for materials.   The roll applicator for a belt-like substrate according to claim 5 or 6, wherein the applicator roll is a rubber-coated roll obtained by lining a metal roll with rubber.   The roll coating apparatus for a strip-shaped substrate according to any one of claims 5 to 7, wherein the slit die includes a suction mechanism that generates a negative pressure upstream of the coating unit.